Ask the Expert: Dr. Xiang Fang

I am always fascinated by how our brain works,” says Dr. Xiang Fang, chief of the Division of Memory Disorders at The University of Texas Medical Branch.

Like any fine-tuned machine, when things are running smoothly it’s easy to overlook the complex interactions that keep the brain functioning.

But, Fang explains, the smallest disruption can cause various diseases from autoimmune brain injury to neurodegenerative disease. And that’s where an expert like him steps in.

Worldwide, more than 55 million people live with dementia, and that number is expected to triple by 2050. In the United States alone, about 6.7 million adults have Alzheimer’s disease, the most common type of dementia.

The emotional, social, and economic costs of treating and living with dementia are staggering and, unfortunately, there is no cure.

But modern medical science continues to push forward with new and better treatments and a deeper understanding of how to prevent dementia in the first place.

As a board-certified neurologist and an award winning scientist, Fang looks at dementia as both a curious researcher and physician who cares about his patients and their loved ones.

While there is still much we don’t know, in the following Q&A with UTMB Magazine, Fang shares the reasons why he says “there is more reason for optimism than ever before.”

Q: Let’s start with the basics. What is dementia? And are dementia and Alzheimer’s disease the same thing?

A: Dementia is not a single disease. It’s a broad term that describes a set of symptoms caused by damage to the brain. These symptoms include problems with memory, attention, language, judgment, and social behavior, and they are severe enough to interfere with everyday life, such as working, driving, or managing finances. Dementia develops as neurons in the brain are progressively lost or damaged.

Alzheimer’s disease is often confused with dementia, but they are not the same. Dementia is the umbrella term, while Alzheimer’s disease is a specific brain disease, and the most common cause of dementia, responsible for about 60 to 80% of cases. Other conditions can also lead to dementia, which is why understanding the underlying cause is so important for diagnosis and treatment.

Q: What causes dementia? Is it hereditary? Is it due to environmental factors like exposure to certain chemicals or types of pollution? Or is it just random?

A: Dementia results from damage to brain cells that disrupts their ability to communicate, leading to progressive cognitive decline. The most common causes are neurodegenerative disorders, particularly Alzheimer’s disease (characterized by amyloid plaques and tau neurofibrillary tangles), and vascular dementia, which arises from reduced cerebral blood flow. Risk and disease progression are often exacerbated by age, genetic susceptibility, and lifestyle factors such as smoking, diabetes, and hypertension. Other potential causes include traumatic brain injury, central nervous system infections, and metabolic or nutritional disorders. Chronic substance abuse, especially long-term alcohol misuse or abuse, can also result in dementia.

Less than 5% of dementia and Alzheimer’s disease are hereditary. Most cases of dementia are sporadic, but genetic factors can increase susceptibility to a wide range of diseases and conditions, including dementia. For example, if an individual carries one copy of the APOE ε4 allele gene, the risk of developing Alzheimer’s disease increases by approximately three- to fourfold. If two copies of the APOE ε4 allele are present (ε4/ε4 genotype), the risk increases further, by approximately ten to twelve-fold.

Long-term exposure to certain environmental pollutants has been linked to a higher risk of dementia, including Alzheimer’s disease.

Fine particulate matter—such as pollution from traffic, industrial emissions, and wildfire smoke—can enter the bloodstream and trigger chronic inflammation. Research suggests this exposure may accelerate the buildup of amyloid plaques and tau tangles in the brain, which are key features of Alzheimer’s disease.

Exposure to heavy metals, including lead, mercury, arsenic, and manganese, has also been associated with cognitive impairment and increased dementia risk. In addition, prolonged or high-level exposure to some agricultural and household pesticides can act as neurotoxins, potentially increasing the likelihood of developing dementia later in life.

Q: What, if anything, can we do to lower our chances of suffering from dementia?

A: According to the 2024 Lancet Commission report, nearly half of dementia cases worldwide may be linked to modifiable risk factors—things we can potentially change or treat across the lifespan. These include addressing hearing loss, high LDL cholesterol, and vision loss, as well as managing conditions such as high blood pressure, obesity, diabetes, and depression. Lifestyle factors also matter, including smoking, excessive alcohol use, physical inactivity, social isolation, air pollution exposure, and brain injury. Education earlier in life also plays an important
protective role.

The takeaway is an encouraging one: dementia is not inevitable. A healthy lifestyle—regular physical activity, a brain-healthy diet such as the Mediterranean-DASH Intervention for Neurodegenerative Delay diet, and optimal treatment of underlying medical conditions—can meaningfully reduce the risk of developing dementia or delay its onset.

Q: What are signs of oncoming dementia?

A: Symptoms like memory loss, confusion, difficulty planning, or changes in personality can be warning signs of dementia—but they can also reflect other medical conditions that are treatable. Common early signs include forgetting recent conversations or events, getting lost in familiar places, needing increasing reminders for everyday tasks, and noticeable changes in mood or behavior.

Early diagnosis matters. Many people with dementia are not aware of or do not report memory problems themselves. That’s why family members and close friends play a crucial role in recognizing changes and encouraging evaluation. Identifying problems early allows for better treatment, planning, and support for both patients and caregivers.

Q: How can you tell the difference between normal memory problems and dementia?

A: Occasional lapses (forgetting a name/ appointment but remembering later), making errors in finances periodically, or misplacing items but retracing steps to find them are usually related to normal aging process. On the other hand, persistent memory loss affecting daily life, inability to retrace steps for lost items, significant confusion, or difficulty with complex tasks is more suggestive of dementia caused by underlying neuron loss in the brain.

Q: There is currently no cure for dementia. Do you think there will be a cure?

A: While there is currently no cure for dementia, there is more reason for optimism than ever before. We now have two fully FDA-approved monoclonal antibody therapies that target amyloid in the brain and have been shown to slow the progression of Alzheimer’s disease in selected patients.

Looking ahead, the future of treatment is likely to be more personalized. Rather than a single solution, advances may come from combination approaches such as immunotherapy, gene-based strategies, and regenerative therapies that aim to slow, stop, or eventually reverse brain damage. These developments mark a major shift in how we think about treating Alzheimer’s disease.

Q: Caring for a loved one with dementia can be taxing. What advice would you give someone who is helping care for a family member with dementia?

A: Caring for a loved one with dementia can be deeply meaningful, but it can also be exhausting. One of the most important things to remember is that caring for yourself is not optional—it’s essential. Burnout helps no one.

Structure and simplicity go a long way. Try to maintain a consistent daily routine, break tasks into manageable steps, and encourage independence whenever possible. Use clear, calm communication, and avoid correcting your loved one when they’re confused or make mistakes. Instead of challenging their reality, respond with patience and gentle redirection—it reduces distress for both of you.

Making the home environment safe, using distraction to manage agitation, and planning ahead for respite or temporary care are all crucial. Reaching out for help is not a sign of failure—it’s a necessary part of sustaining care over time